Safety apparatus for a machine, in particular for a press brake

Abstract

The present invention relates to a safety apparatus for a machine such as a press brake. The machine has a first and a second machine part which perform a working movement towards each other. The first machine part has a leading edge in the direction of movement, and the leading edge defines a plane of movement. The safety apparatus has a plurality of first light barriers which run with the first machine part during the working movement, with the light beams of the first light barriers extending parallel to the plane of movement and being distributed in the region of the plane of movement in such a way that they run in advance of the leading edge with an increasing distance as viewed in the direction of the working movement. Furthermore, there is a control unit which stops the working movement in response to the first light barriers. There is also a configuration device, by means of which selected ones from the first light barriers can be deactivated at least for the duration of the working movement.

1. In a machine having a first machine part and a second machine part, with the first machine part and the second machine part performing a working movement towards each other, and with the first machine part having a leading edge in the direction of the working movement, the leading edge defining a plane of movement, a safety apparatus comprising:
 a plurality of first light barriers arranged for moving together with one of the machine parts during the working movement, 
 a control unit, and 
 a configuration device, 
 wherein the first light barriers are configured to generate a plurality of first light beams extending parallel to the plane of movement, 
 wherein the plurality of first light barriers are arranged such that the first light beams run in advance of the leading edge, and 
 wherein the plurality of first light beams run with a plurality of different distances from the leading edge as viewed in the direction of the working movement, 
 wherein the control unit is configured to stop the working movement of the first machine part in response to the first light barriers, and 
 wherein the configuration device is configured to deactivate selected ones from the first light barriers for at least the duration of the working movement. 
 
   
   
     2. The safety apparatus according to  claim 1 , wherein the configuration device is configured in such a way that the first light barriers can be deactivated only in a reverse sequence of their distance from the leading edge. 
   
   
     3. The safety apparatus of  claim 1 , further comprising a plurality of second light barriers for generating second light grid which lies to one side of the plane of movement but essentially parallel thereto. 
   
   
     4. The safety apparatus according to  claim 3 , wherein the second light barriers are arranged to run with the first machine part during the working movement. 
   
   
     5. The safety apparatus of  claim 3 , wherein the configuration device is configured to deactivate selected ones from the second light barriers at least for the duration of the working movement. 
   
   
     6. The safety apparatus according to  claim 5 , wherein the configuration device is configured to deactivate only those second light barriers which run in advance of a non-deactivated first light barrier as viewed in the direction of the working movement. 
   
   
     7. The safety apparatus of  claim 3 , wherein the plurality of second light barriers includes at least one second light barrier that trails behind the leading edge as viewed in the direction of the working movement. 
   
   
     8. The safety apparatus of  claim 1 , comprising at least four first light barriers, the first light beams of which run at a distance of about 5 mm, about 9 mm, about 15 mm and about 21 mm from the leading edge. 
   
   
     9. The safety apparatus of  claim 1 , wherein the configuration device comprises a part for determining overtravel of the first machine part, with the configuration device further being configured to deactivate the first light barriers only as a function of the overtravel. 
   
   
     10. The safety apparatus of  claim 1 , wherein the configuration device is configured to deactivate the selected ones from the first light barriers permanently. 
   
   
     11. A machine installation for processing workpieces, the machine installation comprising:
 a first machine part and a second machine part, wherein the first machine part is adapted to perform a working movement towards the second machine part, and wherein the first machine part has a leading edge in the direction of the working movement, the leading edge defining a plane of movement, 
 a plurality of first light barriers arranged for moving together with the first machine part during the working movement, wherein the first light barriers are designed to generate light beams that run parallel to the plane of movement and in advance of the leading edge such that each first light beam has a distance from the leading edge as viewed in the direction of the working movement, 
 a control unit configured to stop the working movement in response to the first light beams, and 
 a configuration device configured to deactivate selected ones from the first light barriers at least for the duration of the working movement. 
 
   
   
     12. The machine installation of  claim 11 , wherein the configuration device is configured in such a way that the first light barriers can be deactivated only in a reverse sequence of their distances from the leading edge. 
   
   
     13. The machine installation of  claim 11 , further comprising a plurality of second light barriers for generating second light beams, wherein the second light beams form a light grid lying to one side of the plane of movement but essentially parallel thereto. 
   
   
     14. The machine installation of  claim 13 , wherein the second light barriers are arranged to run with the first machine part during the working movement. 
   
   
     15. The machine installation of  claim 13 , wherein the configuration device is configurated to deactivate selected ones from the second light barriers for at least the duration of the working movement. 
   
   
     16. The machine installation of  claim 15 , wherein the configuration device is configured to deactivate only those second light barriers which run in advance of a non-deactivated first light barrier as viewed in the direction of the working movement. 
   
   
     17. The machine installation of  claim 13 , wherein the plurality of second light barriers includes at least one second light barrier that trails behind the leading edge as viewed in the direction of the working movement. 
   
   
     18. The machine installation of  claim 11 , comprising at least four first light barriers, the first light beams of which run at a distance of about 5 mm, about 9 mm, about 15 mm and about 21 mm from the leading edge. 
   
   
     19. The machine installation of  claim 11 , wherein the configuration device comprises a part for determining overtravel of the first machine part, with the configuration device further being configured to deactivate the first light barriers only as a function of the overtravel. 
   
   
     20. The machine installation of  claim 11 , wherein the first and the second machine part together comprise a punch and a die to form a press brake.